1. Technical Field
The present invention relates to an assembly of a pneumatic tire and a rim, in which a noise damper made of a spongy material is disposed in a tire cavity to reduce a road noise generated during running.
2. Background Art
As one of tire noises is known a so-called road noise which sounds like “GHO” within a frequency range of 50 to 400 Hz when running on a road. A main cause of the road noise is considered a resonance vibration of air (cavity resonance) which generates in the tire cavity.
In order to reduce such a road noise, it is proposed to dispose, as shown in FIG. 13(A), a noise damper “a” which is made of a spongy material and extends circumferentially, in a tire cavity “i” surrounded by a tire “b” and a rim “c”, thereby absorbing a resonance energy generated in the tire cavity “i” (cf. Patent Literature 1). In order to prevent the noise damper “a” from frequently colliding with the inner surface of the tire by centrifugal force and lateral force during running, the noise damper “a” is adhered for example to the inner surface of the tire “b”.
However, as a result of making a durability test on a tire assembly having the noise damper “a” by using a drum durability tester in further investigation of the present inventor, it was found that if the height H of the noise damper “a” is large, swaying or the like is easy to occur at the time of high speed running and, consequently, peeling may occur.
It was also found that, as shown in FIG. 13 (B) in an enlarged form, cracking “g” is easy to occur in the vicinity of the adhesion surface “f” at circumferential both ends “e” of the noise damper “a”. Unlike adhesive peel, cracking “g” is cracking of a spongy material itself and, therefore, it is supposed that cracking also occurs when the adhesive strength to the tire “b” is increased.    Patent Literature 1: JP-A-2003-63208